Add a privacy note to the upgrade wizard

plugins/tiddlywiki/upgrade/UpgradeWizard.tid

@@ -15,6 +15,10 @@ Drag a ~TiddlyWiki file here to upgrade it
 
 or click to pick a file <$browse/>
 
+---
+
+//Your data will not leave your browser. [[Download|http://tiddlywiki.com/upgrade.html]] this upgrader to use it offline//
+
 </$list>
 
 <$reveal state="$:/Import!!status" type="match" text="pending">

plugins/tiddlywiki/upgrade/styles.tid

@@ -23,6 +23,10 @@ tags: $:/tags/stylesheet
 	fill: <<colour foreground>>;
 }
 
+.tw-upgrade-wizard em {
+	color: <<colour tiddler-subtitle-foreground>>;
+}
+
 .tw-upgrade-wizard table {
 	text-align: left;
 }